In recent years, Organic Light-Emitting Diodes (OLEDs) have become a very popular emerging flat panel display product in China and abroad, because OLED displays have the advantages such as self-luminous, wide viewing angle, short reaction time, high luminous efficiency, low operating voltage, thin thickness, large size, flexibility, and simple fabrication process. Moreover, OLED displays have the potential of low cost.
OLEDs can be divided into two categories according to their driving modes: passive driving OLEDs and active driving OLEDs, also known as direct addressing OLEDs and thin film transistor (TFT) matrix addressing OLEDs. Active driving OLEDs are also known as active matrix (AMOLEDs) types. Each light-emitting unit in an AMOLED has a TFT for independent addressing control. A display pixel composed of a light-emitting unit and a TFT addressing circuit needs a power signal wire which applies a direct current signal to drive the pixel.
However, in a large-size AMOLED display device, since the backplane power signal line has a certain resistance R and the drive currents I of these pixels are provided by the power signal, the power voltage received by a region close to the supply position of the power signal is higher than the power voltage received by a region a distance away from the supply position of the power signal. This phenomenon is referred to as IR drop. IR Drop will cause current differences in different regions, affecting the display effect of the device display.